=Development= is effected by pouring warm water about 100° F. over the back of the exposed tissue. So soon as the colour exudes around the edges of the paper backing, the latter may be removed, and the development proceeded with by continuing to pour warm water over the surface. Only a slight impression should remain—the lines showing the bare stone perfectly clear and clean. Allow the stone to dry in a cool, shady place without the application of artificial heat. =Roll Up= with lithographic chalk ink until the surface presents a solid black appearance, stand the stone aside for a few hours to allow the ink to penetrate its surface, and then =Remove the Negative= carbon print from the stone by means of a piece of woollen cloth moistened with a thin solution of gum. This takes some time, but it will be found that the fatty ink has penetrated where unprotected by the carbon negative, and has formed a complete positive. =Gum In=, etch, and proceed as in ordinary lithographic operations. It cannot be expected that the operation, as conducted above, will produce the finest results; the drawing will usually require a certain amount of retouching at the hands of the lithographic artist, who will, however, often be saved a vast amount of trouble. It is obvious that if the proceedings, as described, be carried out, using, however, a photographic glass positive in place of the printed impression, the process will be found capable of giving much finer results, and the exposure will be very materially decreased. TRANSPOSING—BLACK AND WHITE. A modification of the foregoing process may be utilised for the reversal or transposition of black to white, or _vice versa_, of any subject of which a print may be obtained in printing ink. =An Impression= is first obtained either upon sensitised carbon tissue or, preferably, on a thinner paper, coated and sensitised as for photo-lithography. Such paper must not be submitted to a light of much actinic power during or before printing, and as much ink as possible should be used without risk of filling up the work. =Dust Over= the impression while still wet any dense opaque colour, applied by means of wool or camel-hair brush, carefully going over every part and piling on as much colour as possible, after which =Expose the Paper= bearing the print so treated to the light for a short period, dependent upon the light and sensitiveness of the paper. If it be a full impression, well dusted, the latitude in exposure will be very considerable. =Ink Up= the whole surface of the paper with lithographic transfer ink, thinned with turpentine, and applied by means of a sponge or roller.